Page 175 - Moving the Earth_ The Workbook of Excavation

BASEMENTS

BASEMENTS 4.15

walked into the unexcavated north section. When its center is a half-bucket width inside the east
line, as in (D), it stops and shaves the end of the excavation, then trenches to the north edge. It
next straddles the north line, and is lined up in the same manner as before, with the bucket resting
in the hole in the northeast corner.
The north section is excavated in the same manner as described for the south, and completes
the excavation. The west edge may be cleaned up, if necessary, by turning the backhoe to walk
parallel to the edge, so that the bucket can dig straight up. The backhoe should not be put in this
position, however, unless the soil is firm and is known to have good load-bearing qualities, as a
crawler machine is vulnerable to cave-ins or slumping under one track.
This edge may also be trimmed from the north and south banks.
The completed excavation and spoil piles are shown in Fig. 4.14. It will be noticed that the
piles are somewhat offset from the hole, so that the south pile can easily be used for fill on the
east end, and the north pile on the west end. Both ends are left open for access and storage.
The north cut could have been made in the same direction as the south cut, if the east ditch
were shorter, but the fill would then have been concentrated toward the east end.
A more finished hole could be made by starting the digging with a ditch along the west edge,
dug from the south. The spoil pile would largely block the access to that side, unless the soil were
piled in the basement area for rehandling. If access were not important, this ditch could be widened
toward the center, reducing the amount to be piled to south and north. Existence of such a ditch
would make it necessary to work the north section toward the east.

Loading Trucks. A backhoe can load the spoil in trucks instead of dumping it on the ground.
Where the piles will be so large that they will have to be dragged back, a truck or trucks may be
used to take part of it away, the backhoe continuing to dump on the piles when no truck is in load-
ing position. If grading plans have been prepared requiring use of the fill away from the founda-
tion, it may be cheaper to truck it than to push it later with a dozer. However, enough of a pile
should be left by the hole for backfilling between the foundation and the edge of the excavation.
The backhoe can dig footing trenches below the floor level where it is working parallel to the
edge, as along the south, east, and north walls in Fig. 4.13. The hydraulic backhoe can dig them
anywhere, but the parallel position is easiest.

FIGURE 4.14 Finished excavation.